I'm considering buying a small class T digital mini amp like the Topping TP21 or the Lepai TA2020 to power some bookshelf speakers so I can play tunes in my camp. Will it work? These amps come with an AC to DC adapter. I have a deep cycle 12 volt marine battery. If I cut the brick off the adapter, can I wire it directly to my 12 volt battery? If so, how do I know which wire is positive and which is negative?

I haven't checked the Lepai but the Topping is a great unit and it does run on 12 volts DC. Yes, you can cut the "brick" off the power cord and wire it to your deep cycle battery. Most power cords have an identifier for the "hot" or + side, either a stripe or a grooved surface (and the negative side smooth).The best way to know is to either look for a mark or make your own, then when you cut the wire, plug in the "brick" and check with a volt meter to positively identify which wire is + and which is -.

GreyCoyote: "At this rate it wont be long before he is Admiral Fukkit."Delle: Singularly we may be dysfunctional misfits, but together we're magic.

I made a music backpack for bike rides using Logitech computer speakers. Power came from 18v cordless drill battery. On the original battery it would play at full, or close to, volume for just over two hours (and they get effing loud). On a lithium ion drill batt was almost four hours. "But that's not 12v and that's what I asked stupid" Yeah, but my point is they seem pretty efficient. I also ran them off the 12v from my BM solar- battery setup and sound just fine. The ac to dc wall adapter says its 14.4v, about the same as a running automobile, and all these type units should be internally regulated to some degree so that's why some varied voltage range can work. I opened it up and soldered directly onto the power-in side to connect to battery. The adapter is still intact to plug into house too. Good luck.

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Thanks for the replies. I did get an amp, and I went to Marvac's (like Radio Shack) and found a power connector that fits the amp and has alligator clips to connect to a DC battery. So I don't have to butcher the AC-DC adaptor that came with the amp.